Pooling strategy and chromosome painting characterize a living zebroid for the first time.

Alessandra Iannuzzi,Malcolm Ferguson-Smith,Beiyuan Fu,Jorge Pereira,Clara Iannuzzi,Igor V Sharakhov

doi:10.1371/journal.pone.0180158

Abstract

We have investigated the complex karyotype of a living zebra-donkey hybrid for the first time using chromosome-specific painting probes produced from flow-sorted chromosomes from a zebra (Equus burchelli) and horse (Equus caballus). As the chromosomes proved difficult to distinguish from one another, a successful new strategy was devised to resolve the difficulty and characterize each chromosome. This was based on selecting five panels of whole chromosome painting probes that could differentiate zebra and donkey chromosomes by labelling the probes with either FITC or Cy3 fluorochromes. Each panel was hybridized sequentially to the same G-Q-banded metaphases and the results combined so that every zebra and donkey chromosome in each suitable metaphase could be identified. A diploid number of 2n = 53, XY was found, containing haploid sets of 22 chromosomes from the zebra and 31 chromosomes from the donkey, without evidence of chromosome rearrangement. This new strategy, developed for the first time, may have several applications in the resolution of other complex hybrid karyotypes and chromosomal aberrations.

Highlights

In recent times animal breeders and zoos have created, either by accident or design, a spectacular range of mammalian hybrids, from Grizzly-Polar bear, Coywolf, Savannah cat and Liger, to Zebroids [1,2], Dzo [3], Beefalo [4] (American bison and cattle), geep [5,6–7] and Cama
In this study we report the complete chromosomal characterization about one of zebroids mentioned above, using chromosome painting, pooling strategy and sequential Multicolour fluorescence in situ hybridization (M-FISH) for the first time in a hybrid
The Equus burchelli (EBU) probes reveal chromosome fusions and fissions that have occurred during the divergence of the two species and indicate the regions of EBU homology on Equus asinus (EAS) chromosomes that allow the identification of EAS chromosomes

Summary

Introduction

In recent times animal breeders and zoos have created, either by accident or design, a spectacular range of mammalian hybrids, from Grizzly-Polar bear, Coywolf, Savannah cat and Liger (lion-tiger), to Zebroids [1,2], Dzo [3] (cattle-Yak), Beefalo [4] (American bison and cattle), geep [5,6–7] (sheep-goat) and Cama (camel-llama). Most of these hybrids have been studied using conventional cytogenetics, with no banding results and no information about chromosomal rearrangements.

Objectives

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Conclusion